应用程序Windows窗体C＃使用菜单（用户控件）

Question

I have an application with 2 Forms, for those forms I have create a Menu which I depose on the two forms.

There is only a menuStrip item on the menu, I just want when I click on "test1" to redirect to Form1 and when I click to "test2" I want to redirect to Form2.

But if test1 is already open/display I don't want to show him again and the same for test2.

My code in my Menu :

 public partial class Menu : UserControl
{
    public Menu()
    {
        InitializeComponent();
    }

    private void test1ToolStripMenuItem_Click(object sender, EventArgs e)
    {
        Form1 f1 = new Form1();
        Form2 f2 = new Form2();
        f2.Hide();
        f1.Hide();
        f1.ShowDialog();
    }

    private void test2ToolStripMenuItem_Click(object sender, EventArgs e)
    {
        Form1 f1 = new Form1();
        Form2 f2 = new Form2();
        f1.Hide();
        f2.Hide();
        f2.ShowDialog();
    }
}

My Form1 :

My Form2 :

I just want the same result like my Buttons in Form1 and Form2 :

public partial class Form2 : Form
{
    public Form2()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        this.Hide();
        Form1 f1 = new Form1();

        f1.ShowDialog();
    }

}

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        this.Hide();
        Form2 f2 = new Form2();

        f2.ShowDialog();
    }
}

I thought that the property Visible for forms could help me but not...

The problem is when I click on my buttons it's open a new window but when my form is already open I don't want to open it again.

Thanks for your reply, I hope that I am clear sorry for my english in advance.

Answer 1

You are currently creating a new form each time the click handler code is executed.

Here is one way, but its nasty and I wouldn't really recommend it. I've assumed that form1 is the entry to your application and that its also the exit of the application. This solution uses a singleton to hold the f1/f2 instances.

public static class Global
{
    static Global()
    {
        f2 = new Form2();
    }
    public static Form f1;
    public static Form f2;
}

Your menu altered:

public partial class Menu : UserControl
{
    public Menu()
    {
        InitializeComponent();
    }

    private void toolStripButton1_Click(object sender, EventArgs e)
    {
        Global.f2.Hide();
        Global.f1.Hide();
        Global.f1.Show();
    }

    private void toolStripButton2_Click(object sender, EventArgs e)
    {
        Global.f1.Hide();
        Global.f2.Hide();
        Global.f2.Show();
    }

    public void SetForm1(Form form)
    {
        Global.f1 = form;
    }

    public void SetForm2(Form form)
    {
        Global.f2 = form;
    }
}

And the forms:

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();

        Global.f1 = this;
    }

    private void button1_Click(object sender, EventArgs e)
    {
        this.Hide();
        Global.f2.ShowDialog();
    }
}
public partial class Form2 : Form
{
    public Form2()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        this.Close();
        Global.f1.Show();
    }
}

Hope this helps.

Answer 2

Your logic is wrong.

It seems to me that you want to display different content depending on the user selection on that 'menuStrip'. You need to look at dynamic controls loading not different forms loading.

You can have just a MainForm with that 'menuStrip' and a Panel. Define some User Controls and dynamically add them to that panel based on the user selection.

Snippet

public MainForm : Form
{
    public MainForm()
    {
         // code
    }

    public void MenuStrip_OptionSelected(object sender, EventArgs e)
    {
        Panel1.Controls.Clear();
        switch(MenuStrip.SelectedValue)
        {
            case "UserControl1" : Panel1.Controls.Add(new UserControl1()); break;
            ...
        }
    }
}


public UserControl1 : UserControl
{
    // code
}